Process for reducing contaminating Michael acceptor levels in oxycodone and other compositions

ABSTRACT

The present invention relates to processes for removal of Michael acceptors from certain compositions wherein the composition is treated with a thiol-containing compound under conditions sufficient to remove Michael acceptors and the resulting thiol-Michael adducts. Certain embodiments of the present invention enable quantification and/or removal of Michael acceptors and/or Michael acceptor precursors.

RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent ApplicationSer. No. 60/739,087, filed Nov. 22, 2005.

BACKGROUND OF THE INVENTION

The presence of Michael acceptors as contaminants in pharmaceuticalagents, food or other compositions that might be internalized by livingorganisms is generally undesirable, since Michael acceptors can undergocytotoxic reactions with nucleophilic cellular constituents. Ofparticular concern are potentially genotoxic reactions of Michaelacceptors with nucleic acid nucleophiles (e.g. Chem. Res. Toxicol. 2004,17, 827-838; Chem. Res. Toxicol. 1991, 4, 50-7; Environmental HealthPerspectives 1990, 88, 99-106).

Interestingly, animals have defense systems for deactivatinginternalized or metabolically generated Michael acceptors. One suchdeactivating system involves reaction of Michael acceptors with theendogenous cellular nucleophile, reduced glutathione, to formglutathione adducts (for a review see Advances in Enzyme Regulation1993, 33, 281-296). Recent studies (Bioorg. Med. Chem. 1999, 7,2849-2855; Chem. Commun. 2005, 886-888) indicate that this reaction isreversible. Thus, the genotoxic and carcinogenic potential of Michaelacceptors may reflect a failure of the Michael acceptor to undergocomplete reaction with glutathione or reversal of thiol addition.Consequently, it is important to minimize the amount of Michael acceptorcontaminants (or Michael acceptor precursors) that are present in drugsand other products meant for administration to living organisms.

A recently published patent application (20050222188A1) entitled,“Process for preparing oxycodone hydrochloride having less than 25 PPM14-hydroxycodeinone” describes a method for removal of the Michaelacceptor 14-hydroxycodeinone from the analgesic composition oxycodonethat involves hydrogenating in acidic solution an oxycodonehydrochloride composition that contains contaminating14-hydroxycodeinone.

Whereas techniques like those described in 20050222188A1 (and elsewhere)exist for removal and detection of Michael acceptor contaminants,improvements would increase the safety of drugs and other compositionsconsumed by living organisms.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 depicts a plot used to determine the 14-hydroxycodeinone (14-HC)content of the oxycodone product of Example 1B with sodiumthioglycolate.

FIG. 2 depicts a plot used to determine the 14-hydroxycodeinone (14-HC)content of the oxycodone product of Example 5 with sodium thioglycolate.

FIG. 3 depicts a plot used to determine the 14-hydroxycodeinone (14-HC)content of the oxycodone product of Example 8 with sodium thioglycolate.

FIG. 4 depicts a plot used to determine the 14-hydroxycodeinone (14-HC)content of the oxycodone product of Example 11 with sodiumthioglycolate.

FIG. 5 depicts a plot used to determine the 14-hydroxycodeinone (14-HC)content of the oxycodone product of Example 13 with sodiumthioglycolate.

FIG. 6 depicts a plot used to determine the 14-hydroxycodeinone (14-HC)content of the oxycodone product of Example 15 with sodiumthioglycolate.

FIG. 7 depicts a plot used to determine the 14-hydroxycodeinone (14-HC)content of the oxycodone product of Example 13 with sodium thioglycolateusing reduced amounts of sample.

FIG. 8 depicts a plot used to determine the 14-hydroxycodeinone (14-HC)content of the oxycodone product of Example 13 with5-mercapto-2-nitro-benzoic acid.

FIG. 9 depicts a plot used to determine the 14-hydroxycodeinone (14-HC)content of an oxycodone hydrochloride composition with5-mercapto-2-nitro-benzoic acid.

FIG. 10 depicts a plot used to determine the 14-hydroxycodeinone (14-HC)content of the oxycodone hydrochloride product of Example 22 withN-dansyl-L-cysteine.

SUMMARY OF THE INVENTION

The present invention, in one aspect, involves the processes as recitedin the appended claims.

The present invention relates to processes for removal of Michaelacceptors, and/or precursors thereof, from drugs or other compositionsthat contain ingredients that may be internalized by living organisms orcompositions that might contact ingredients meant to be internalized byliving organisms, wherein the composition is treated with athiol-containing compound under conditions sufficient to remove Michaelacceptors and thiol-Michael adducts. Where the text below refers to aprocess, it is to be understood that any of the processes describedherein can apply.

In one aspect the invention provides a series of processes. One processinvolves removing at least one Michael acceptor from one or anycombination of the following compositions: a composition that may beinternalized by a living organism; a composition that may be in contactwith a living organism; or a composition that may be in contact withmaterials suitable for internalization by a living organism; comprisingtreating the composition with a thiol-containing compound underconditions sufficient to remove at least a portion of the at least oneMichael acceptor and/or a thiol-Michael adduct which can form fromaddition of the thiol-containing compound to the at least one Michaelacceptor.

Another process of the invention involves removing at least one Michaelacceptor from one or any combination of the following compositions: acomposition that may be internalized by a living organism; a compositionthat may be in contact with a living organism; or a composition that maybe in contact with materials suitable for internalization by a livingorganism; comprising treating the composition with a suitable solublethiol-containing compound under conditions sufficient to react with theat least one Michael acceptor, and removing from the composition theresulting thiol-Michael adduct, and the unreacted thiol-containingcompound, wherein the thiol-containing compound is chosen for itsability to form a soluble thiol-Michael adduct that can be removed fromthe composition of interest, and, when desirable, quantified, so as toenable determination of the Michael acceptor content of the compositionof interest.

In processes of the invention, the composition of interest can betreated with a suitable thiol which has been immobilized on a solidsupport. The composition of interest can be selected from one or anycombination of the following compositions: oxycodone; hydrocodone;oxymorphone; hydromorphone; naloxone; naltrexone or acceptable saltthereof; related alkaloid or acceptable salt thereof.

Processes of the invention can include producing a product, wherein nosingle Michael acceptor or salt thereof is present in an amountexceeding 5 ppm, or exceeding 10 or 25 ppm.

Product can be produced wherein no single thiol-Michael adduct or saltthereof is present in an amount exceeding 25 ppm. Product can beproduced which contains oxycodone or acceptable salt thereof thatcontains 14-hydroxycodeinone or salt thereof in an amount of less than25, less than 10, less than 5, or less than 1 ppm.

Product can be produced which contains oxycodone or acceptable saltthereof that contains 14-hydroxycodeinone or salt thereof in an amountof less than 1 ppm. Product can be produced which contains naltrexone oracceptable salt thereof that contains 7,8-dehydronaltrexone or saltthereof in an amount of less than 25, less than 10, less than 5, or lessthan 1 ppm.

Processes of the invention can also involve quantifying at least oneMichael acceptor wherein the amount of thiol-Michael adduct is measuredand related to the Michael acceptor content of the composition, andwherein the limit of quantification of the amount of any one Michaelacceptor contaminant is 10 ppm or less, or wherein the limit ofquantification of the amount of any one Michael acceptor contaminant isin the range of 0.001-10 ppm.

Processes of the invention can also involve quantifying the Michaelacceptor content of one or any combination of the followingcompositions: oxycodone; hydrocodone; oxymorphone; hydromorphone;naloxone; naltrexone or acceptable salt thereof; or related alkaloid oracceptable salt thereof; wherein the amount of thiol-Michael adduct ismeasured and related to the Michael acceptor content of the composition,and wherein the limit of quantification of the amount of any one Michaelacceptor contaminant is 10 ppm or less, or 1 ppm or less, or in therange of 0.001-10 ppm.

Processes of the invention can also involve quantifying the14-hydroxycodeinone content of oxycodone or acceptable salt thereofwherein the amount of thiol-Michael adduct of 14-hydroxycodeinone ismeasured and related to the 14-hydroxycodeinone content of thecomposition, and wherein the limit of quantification of the level of the14-hydroxycodeinone contaminant is 10 ppm or less, or less than 1 ppm,or within the range 0.001-10 ppm.

In processes of the invention, the composition of interest can be anorganic base whose solubility in water decreases with increasing pH; andwherein the composition of interest is treated with a suitablethiol-containing compound in aqueous solution at a suitable pH value toform (with the contaminating Michael acceptor) a soluble thiol-Michaeladduct; and wherein the organic base of interest is then separated fromthe thiol-Michael adduct and excess thiol-containing compound by raisingthe pH to a suitable value so as to precipitate the composition ofinterest from the solution of soluble thiol-Michael adduct and excessthiol-containing compound.

In processes of the invention, the composition of interest can be anorganic acid whose solubility in water decreases with decreasing pH; andwherein the composition of interest is treated with a suitablethiol-containing compound in aqueous solution at a suitable pH value toform (with the contaminating Michael acceptor) a soluble thiol-Michaeladduct; and wherein the organic acid of interest is then separated fromthe thiol-Michael adduct and excess thiol-containing compound bylowering the pH to a suitable value so as to precipitate the compositionof interest from the solution of soluble thiol-Michael adduct and excessthiol-containing compound.

In processes of the invention, the composition of interest can beseparated from thiol-Michael adduct and excess thiol-containing compoundby selective precipitation and/or extraction utilizing water and/orother solvents and/or by selective absorption on media, such as, but notrestricted to, ion-exchange resins, and/or other solid supportscontaining immobilized liganded metal ions, and/or immobilizedmaleimides, and/or immobilized reactive disulfides, and/or immobilizedantibodies and/or immobilized enzymes.

Another process of the invention involves removing at least one Michaelacceptor and/or at least one Michael acceptor hydrate from one or anycombination of the following compositions: a composition that may beinternalized by a living organism; a composition that may be in contactwith a living organism; or a composition that may be in contact withmaterials suitable for internalization by a living organism; comprisingtreating the composition with an acid catalyst under conditionssufficient to remove at least one Michael acceptor hydrate by convertingthat one Michael acceptor hydrate to a Michael acceptor; and thentreating the composition with a suitable soluble thiol-containingcompound under conditions sufficient to remove from the composition theunreacted thiol-containing compound, at least one Michael acceptororiginally present in the composition; and the Michael acceptor formedfrom the at least one Michael hydrate; and wherein the thiol-containingcompound is chosen for its ability to form a soluble thiol-Michaeladduct(s) that can be removed from the composition of interest, and,when desirable, quantified, so as to enable determination of the Michaelacceptor hydrate content and the Michael acceptor content of thecomposition of interest. In this or other processes of the invention,the process can involve producing a product containing oxycodone oracceptable salt thereof that contains 8-hydroxyoxycodone or salt thereofin an amount of less than 100 ppm, or less than 10 ppm or less than 5ppm. In this or other processes of the invention, the process caninvolve producing a product containing naltrexone or acceptable saltthereof that contains 8-hydroxynaltrexone or salt thereof in an amountof less than 100 ppm, or less than 10 ppm or less than 5 ppm.

The invention also provides a series of products, which can be producedaccording to processes described herein, or can be products which areessentially similar or identical to products which can be produced byprocesses of the invention. Any products which are described herein orwould result from processes described herein are within the scope of theinvention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to processes for removal of Michaelacceptors, and precursors thereof, from drugs or other compositions thatcontain ingredients that may be internalized by living organisms orcompositions that may contact ingredients meant to be internalized byliving organisms, wherein the composition is treated with athiol-containing compound under conditions sufficient to remove Michaelacceptors and thiol-Michael adducts. Where the text below refers to aprocess, it is to be understood that any of the processes describedherein can apply.

Definitions, as used herein:

“Michael acceptor” means an α,β-unsaturated electrophile, such as, butnot limited to, an α,β-unsaturated carbonyl derivative or anα,β-unsaturated nitrile.

It is to be understood that within the context of the definition ofMichael acceptor: “Electrophile” means able to accept an electron pair;“α,β-unsaturated electrophile” means the compound class that includes,but is not limited to, α, β-unsaturated carbonyl derivative,α,β-unsaturated nitrile, α,β-unsaturated sulfone, or other vinylderivative substituted with a strong electron withdrawing group, suchas, but not limited to, a nitro group; “α,β-unsaturated carbonylderivative” means the compound class that includes, but is not limitedto, α,β-unsaturated ketone, quinone or derivative thereof,α,β-unsaturated aldehyde, α,β-unsaturated carboxylic acid derivative,such as, but not limited to, an ester, an amide, a substituted amide, ora maleimide or a derivative thereof.

“Thiol,” or “thiol-containing compound,” or “thiols” or“thiol-containing compounds” means thiol-containing compound, orcompounds, except wherein the context of its use indicates a thiolmoiety, or group, as in the term “thiol functionalized”. Those ofordinary skill in the art are aware that a “thiol” is asulfur-containing compound, generally a sulfur-containing organiccompound.

“Thiol-Michael adduct” means a thioether, or mixture of thioethers,formed as a result of the addition of a thiol-containing compound to theMichael acceptor.

“Mercapto-thiol-Michael adduct” means a mercapto-thioether, or mixtureof mercapto-thioethers, that form when a Michael acceptor reacts with anexcess of a dithiol or polythiol (a compound containing at least twothiol groups).

“Michael acceptor precursor” means any substance (including athiol-Michael adduct or Michael acceptor hydrate) that may undergoconversion to a Michael acceptor under conditions consistent with anenvironment in which the substance may exist in the context of thepresent invention. For example, a Michael acceptor precursor, in thecontext of a pharmaceutical or other therapeutic formulation, is asubstance that can undergo conversion to a Michael acceptor as a resultof conditions under which a pharmaceutical or therapeutic compositioncan exist during its synthesis, formation, storage, and/or use, whetherprior to or after administration to a subject. A Michael acceptorhydrate is an example of a Michael acceptor precursor.

“Michael acceptor hydrate” means the product of addition of water to anα,β-unsaturated electrophile such as, but not limited to, aβ-hydroxyketone.

“Processed composition” or “processed product” means a composition thathas been subjected to a process of the present invention.

“HPLC” means high performance liquid chromatography.

“PPM” or “ppm” means parts per million by weight.

“Acceptable rate” means a rate consistent with the manufacturing cycletime needed to produce a competitively priced processed product.

“Suitable thiol,” or, “Thiol suitable for Michael acceptor and/orprecursor removal,” means a thiol-containing compound that enablesefficient removal of Michael acceptor and thiol-Michael adduct so as toenable production of a competitively priced processed product.Considerations and methods for selecting a suitable thiol-containingcompound are described herein.

“Removing,” “remove,” “removed” or “removal,” as used herein, pertainsto reducing an amount, or reduction of an amount, of at least oneMichael acceptor and/or corresponding thiol-Michael adduct, and/or thiolcontaining compound. In one set of embodiments, such species are removedby a factor of 5, 10, 20, 40, 60, 100, 500 or more. In another set ofembodiments, removing involves removal of such species in an amountsufficient to detect the presence, concentration, and/or amount of suchspecies in a composition.

“Separating,” “separate,” “separated” or “separation,” as used herein,when pertaining to an operation, pertains to dividing up one or morecompositions into two or more portions wherein certain components areenriched in one portion and others are enriched in other portionsincluding situations where certain components are essentially completelydepleted from at least one portion. For example, when components areseparated by distribution between two phases (e.g. two immiscibleliquids or a solid precipitate and liquid phase) the content of one ormore components is enriched in one phase and depleted in the other. Itis to be understood that compositions enriched in one phase may be alsopresent in the other albeit at a lower level.

A “composition that may be internalized by a living organism” is aphrase that will be understood to those of ordinary skill in the art toinclude, but not be limited to, foods, pharmaceutical products, and thelike.

A “composition that may be in contact with materials suitable forinternalization by a living organism” is a phrase that would beunderstood by those of ordinary skill in the art to include, but not belimited to, pharmaceutical delivery equipment, food packaging, and othercompositions and/or materials which are or/may be routinely in contactwith compositions internalized by living organisms by preparation,storage, or use of such materials.

A “Michael acceptor, or electrophile, that can react with a nucleicacid” includes such species which can interact adversely with a nucleicacid, for example, species which can participate in potentiallygenotoxic reactions with nucleic acid nucleophiles.

Reaction of Michael acceptors with organic thiols to form thiol-Michaeladducts is a well-documented reaction (Chem. Commun. 2005, 669-671 andwork cited therein). The reaction has been shown to proceed in water andorganic solvents. Both acidic and basic catalysts have been used tofacilitate thiol-Michael adduct formation and minimize side reactions.

The documented reversibility of thiol-Michael adduct formation (Bioorg.Med. Chem. 1999, 7, 2849-2855; Chem. Commun. 2005, 886-888) suggeststhat removal of Michael acceptors from compositions using thiol reagentsso as to produce products wherein the Michael acceptor level has beenlowered by a factor of 20 or more will be problematical.

However, the teachings of this present invention, including the appendedexamples and claims, show how Michael acceptor levels can be reduced, insome embodiments, by over 20-fold to produce processed products withMichael acceptor levels below 10 ppm or other levels described herein;moreover, the teachings of the present invention, including the appendedexamples and claims, show how to quantify Michael acceptor levels with alimit of quantification at or below 10 ppm or other levels describedherein.

Published literature (Bioorg. Med. Chem. 1999 7, 2849-2855; Chem.Commun. 2005, 886-888) indicates that in aqueous solution the rate ofaddition of a thiol to a Michael acceptor increases with increasing pHdue to increased formation of thiolate anion. Thus, the inventionappreciates that the observed pseudo first-order rate constant k_(R) forformation of the thiol-Michael adduct (TM), should vary with the totalconcentration of thiol ([T]_(t)=[TH]+[T⁻]), Michael acceptorconcentration [M], and hydrogen ion concentration [H⁺], according to theequationk _(R) =k _(s−) [T] _(t)/(1+[H ⁺ ]/K _(SH))

where k_(s−) is the rate constant for reaction of the thiolate anion(T⁻) with the Michael acceptor (M), and K_(SH) is the acid dissociationconstant for the thiol (TH).

It follows from the law of microscopic reversibility that the rate ofelimination of thiolate anion from a thiol-Michael adduct is dependenton the fraction of thiol-Michael adduct existing as a carbanion. Thus,the overall reaction can be represented as proceeding via the followingthree-step reaction pathway.

The first and third steps of the reaction pathway involve protontransfer reactions that appear to be diffusion controlled in thethermodynamically favored direction, whereas the rates of adductformation and decomposition in the second step appear to be the ratedetermining steps for the overall reaction pathway. The rate andposition of the equilibrium for addition of thiolate anion to theMichael acceptor will, of course, reflect the properties of the thiolateanion and the Michael acceptor. These considerations account forobservations that the rate of equilibration of thiol, Michael acceptor,and thiol-Michael adduct increases with increasing pH. The observation(Bioorg. Med. Chem. 1999, 7, 2849-2855), that the extent of adductformation at equilibrium decreases with increasing pH, however, has notbeen accounted for quantitatively.

From the equation for the overall reaction,

and the equilibrium expressions for the overall reaction and theionization of the thiol groupK _(R) =[TM]/[TH][M] K _(SH) =[T ⁻ ][H]/[TH]

it follows that[TM]/[M]=K _(R) [T] _(t)/(1+K _(SH) /[H ⁺]).

This expression allows for the first time, as a contribution made bythis invention, quantitative prediction of the dependence of theequilibrium concentration ratio of thiol-Michael adduct [TM] and Michaelacceptor [M] on the hydrogen ion concentration. The latter expressiontogether with the expression for K_(R) described herein teaches howdecreasing the hydrogen ion concentration decreases the extent ofthiol-Michael adduct formation and increases the rate of adductformation, and enables the design of the processes of the presentinvention for the removal of Michael acceptors from oxycodone and othercompositions.

Oxycodone is a semisynthetic opiate produced via an oxidative conversionof the natural product thebaine to 14-hydroxycodeinone as depicted inthe following scheme.

The oxycodone precursor 14-hydroxycodeinone is a Michael acceptor thatcommonly contaminates oxycodone preparations. The process of thisinvention for Michael acceptor removal is useful for removing14-hydroxycodeinone from oxycodone. It involves treating oxycodone witha thiol so as to convert 14-hydroxycodeinone to a thiol-Michael adduct.In one embodiment of the invention the reaction is carried out in waterat a suitable pH. The pH is chosen so as to allow one to obtain both areasonably concentrated homogenous solution of oxycodone and areasonable rate of reaction consistent with the production of acompetitively priced oxycodone processed product. For formation of athiol-Michael adduct in water in certain embodiments of this invention,a water soluble thiol is chosen so as to form a thiol-Michael adducthaving properties that enable reduction of the Michael acceptor contentto less than 10 ppm. In other embodiments Michael acceptor content isreduced to less than 2000, 1000, 500, 200, 100, 50, 25, 10, 5, 2, 1,0.5, or 0.25 ppm in accordance with the invention. The invention alsocan reduce Michael acceptor levels by over 20-fold, for example at least40-fold, 60-fold, 80-fold, 100-fold, 500-fold, 1,000-fold, or at least2,000-fold. In one application of the invention to the purification ofoxycodone, a 7.5% oxycodone solution is treated at pH 6 with 20 mMsodium thioglycolate and 2 mM EDTA (added to suppress trace metal ioncatalyzed thiol oxidation) for 2.8 hours at room temperature.

The knowledge that oxycodone solubility increases with increases in thehydrogen ion concentration [H⁺] according to the following relationship,

Total concentration of dissolvedoxycodone=[Oxy]_(s)+[OxyH⁺]=[Oxy]_(s)(1+[H⁺]/K),

where [Oxy]_(s) is the solubility of oxycodone free base, and K is theacid dissociation constant for the conjugate acid of oxycodone (OxyH⁺),the relationship between k_(R), the thiol concentration, and hydrogenion concentration disclosed above, and the understanding that the rateof reaction increases with temperature, in conjunction with thedisclosures herein, enables one skilled in the art to efficientlyidentify other desirable reaction conditions. For example, one couldcarry out a homogenous reaction at a substantially higher oxycodoneconcentration by lowering the pH to increase the obtainable amount ofdissolved oxycodone. To compensate for the lowered reaction rate atlower pH, one skilled in the art, guided by factors described hereincan, if necessary, suitably increase the concentration of thiol, and/orthe temperature, and/or the reaction time.

Well-established analytical methods, such as those utilizing highperformance liquid chromatography or gas chromatography linked tosystems that monitor a property of the effluent stream such asabsorbance, fluorescence, light scattering, conductance, refractiveindex or mass spectrum, can be employed by one skilled in the art toquantify the build-up of thiol-Michael adduct in acid quenched reactionmixtures, and thereby characterize the time dependence of the conversionof Michael acceptor to thiol-Michael adduct as a function of thiolstructure, thiol concentration, reaction medium, and temperature. Forexample, if one reacts a Michael acceptor in the presence of a greaterthan ten-fold molar excess of thiol while keeping the fraction of thiolpresent as thiolate anion constant (in water, by maintaining a constantpH during the reaction by addition of acid or base, or by addition of asuitable buffer; in an organic solvent, by the addition of an organicacid or base or mixtures thereof), one skilled in the art can determinea pseudo first-order rate constant for the formation of thiol-Michaeladduct. Since this pseudo first-order rate constant is proportional tothe thiolate anion concentration as described herein, as well as afunction of the structure of the thiol and temperature, measurements ofthe pseudo first-order rate constant for a small number of reactionsenables one to efficiently select a suitable thiol, a suitable thiolconcentration, a suitable pH (for reactions in water) or base (forreactions in an organic solvent), a suitable time, and a suitabletemperature for obtaining an acceptable extent of conversion tothiol-Michael adduct. A reaction mixture, comprised of 20 mM thiol with0.1-10% of the thiol present as thiolate anion (obtained by appropriateadjustment of pH (for reactions in water) or by addition of anappropriate base (for reactions in an organic solvent)), and <2 mMMichael acceptor in the presence or absence of the composition ofinterest, is usually a suitable starting point for a screen to identifyoptimal reaction conditions.

Subsequent to thiol-Michael adduct formation, the composition ofinterest can be removed from thiol-Michael adduct and/or excess thiol incertain embodiments of this invention. This removal can be in largeamount, for example for modification of a composition to render itsuitable for human consumption or other clinical use, or removal can bein a different amount (e.g., smaller amount) for detection/determinationof the presence and/or quantity of a Michael acceptor in a composition.Suitable thiols for use in the reaction include, but are not limited to,those described herein including those noted in the appended claims. Asdiscussed in the following paragraphs, and illustrated in the examplesand the appended claims, the suitability of the thiol is dependent onthe composition of interest and the context of the use of the thiol.

Suitable thiols are ones that can be efficiently removed from thecomposition of interest and form thiol-Michael adducts that can beefficiently removed from the composition of interest, and formthiol-Michael adducts that undergo little or no conversion back toMichael acceptor under conditions used to remove the thiol-Michaeladduct from the composition of interest, and undergo no substantialconversion back to Michael acceptor after internalization (in caseswhere the thiol-Michael adduct is not adequately removed from thecomposition of interest). In cases where the thiol-Michael adduct isretained in the processed composition, it is necessary to demonstratethat, during the shelf life of the processed composition, the amount ofthiol-Michael adduct formed from the thiol-Michael adduct retained inthe processed composition is not a cause for concern by individuals andagencies competent to oversee the safety of food or drugs or medicaldevices.

The stability of a thiol-Michael adduct in a particular medium (e.g.,the media being considered for separation of the composition of interestfrom the thiol-Michael adduct, or physiological fluids that thethiol-Michael adduct is likely to contact after internalization) orduring storage can be evaluated from measurements of the time-dependentdecrease in thiol-Michael adduct concentration.

In certain embodiments of the present invention, processed products areproduced with a Michael acceptor level that is less than 100, 10, 5, 2,1, 0.5, 0.1 or 0.01 ppm and a thiol-Michael adduct level that is lessthan 500, 100, 10, 5, 2, 1, 0.5, 0.1, or 0.01 ppm.

Embodiments of the present invention include processes wherein solublethiol-containing compounds are chosen so as to form solublethiol-Michael adducts that can be effectively removed from a compositionof interest, and facilitate quantification of low levels of Michaelacceptor contaminants in a composition that would otherwise be difficultto measure directly due to interference from the composition ofinterest. Thus, in certain embodiments of the present invention, theMichael acceptor content of a composition is determined by treating thecomposition with a suitable thiol-containing compound, removing thethiol-Michael adduct from the composition of interest and/orthiol-containing compound to enable quantification of the thiol-Michaeladduct, and relating the amount of thiol-Michael adduct to the Michaelacceptor in the composition of interest. Well-established analyticalmethods, such as those utilizing high performance liquid chromatographyor gas chromatography linked to systems that monitor a property of theeffluent stream such as absorbance, fluorescence, light scattering,conductance, refractive index or mass spectrum of the effluent stream,can be used by one skilled in the art to quantify thiol-Michael adducts.Thus, certain embodiments of the present invention quantify Michaelacceptor levels in processed and unprocessed compositions of interestwith a limit of quantification that is less than 100, 10, 5, 1, 0.1 and0.01 ppm.

In embodiments of the present invention wherein subsequent to thioladduct formation the thiol-Michael adduct, and/or excess thiol isremoved from the composition of interest, the thiol is chosen so as toendow the thiol-Michael adduct with properties that differ from those ofthe composition of interest. These properties include, but are notrestricted to, a different solubility in an organic solvent orwater/organic solvent mixtures, or in water at a suitable pH value,and/or a different affinity for an ion-exchange resin and/or anothersolid medium, such as one containing an immobilized disulfide-containingcompound, an immobilized maleimide-containing compound, and/or adifferent affinity on an immobilized antibody or fragment thereof, or animmobilized enzyme or fragment thereof.

The following considerations nicely illustrate how the teachings of thepresent invention guide the choice of a suitable thiol-containingcompound. Subsequent to formation of thiol-Michael adduct at pH˜6 in oneembodiment of the process used to remove 14-hydroxycodeinone fromoxycodone, the pH of the reaction mixture is increased to precipitateand/or extract oxycodone free base from an aqueous solution with most ofthe thiol-Michael adduct and excess sodium thioglyclolate remaining inaqueous solution. The already mentioned expression for the pH-dependenceof oxycodone solubility in water indicates the desirability of a basicpH for efficient precipitation and/or extraction of oxycodone free base.The relationship [TM]/[M]=K_(R)[T]_(t)/(1+K_(SH)/[H⁺]) disclosed in theteachings of the present invention indicates that raising the pH to 9will result in little conversion of the thiol-Michael adduct (formed atpH˜6 where oxycodone is soluble) back to 14-hydroxycodeinone when sodiumthioglycolate (pK_(SH) 10.3) is used. With a thiol with a pK_(SH) of10.3, raising the pH from 6 to 9 would result in only a 5% decrease inthe equilibrium ratio [TM]/[M]. Thus, under conditions whereinthiol-adduct formation is highly favored at pH 6 for at specified thiolconcentration, raising the pH from 6 to 9 would only increase theMichael acceptor content by 5%. Using a pK 9 thiol, however, would leadto a two-fold decrease in the equilibrium ratio [TM]/[M] when the pH isincreased from 6 to 9. Lowering the pH used for precipitating orextracting the oxycodone would, of course, decrease the extent of theback reaction but would also make it more difficult to recover oxycodoneproduct because lowering the pH increases the aqueous solubility ofoxycodone. Examples included in the present invention illustrateprocesses that use a lower pH for precipitation and/or extraction ofoxycodone and/or processes that use lower pK thiols. It is interestingto note that although 5-mercapto-2-nitro-benzoic acid (pK 4.8) is notreadily compatible with a process involving precipitation and/orextraction of oxycodone from a basic solution containing thethiol-Michael adduct formed from 5-mercapto-2-nitro-benzoic acid, thisthiol-containing compound can be employed for processes (especiallyprocesses that involve quantification of a Michael acceptor contaminantin a composition) that utilize other methods to remove Michael acceptorfrom thiol-Michael adduct and unreacted thiol.

Thus, in certain embodiments of the present invention subsequent totreatment with the thiol-containing compound, the composition ofinterest is substantially removed from thiol-Michael adduct and excessthiol-containing compound by, but not restricted to, one or anycombination of the following operations: selective precipitation from anaqueous solution induced by adjustment of the pH of the solution;selective extraction into a water immiscible solvent from an aqueoussolution with, when appropriate, adjustment of the pH (to facilitateextraction), the thiol-content (to suppress thiol-Michael adductdecomposition), and the salt content (to facilitate phase separation) ofthe aqueous solution; selective precipitation from an aqueous solutionby addition of one or more water miscible organic solvents; selectiveextraction from a water immiscible organic solvent into an aqueoussolution at an appropriate pH, and thiol-content; selectiveprecipitation from a water miscible organic solvent by addition of anaqueous solution; selective precipitation from an organic solvent or amixture of organic solvents by addition of a second organic solvent ormixture of organic solvents; high performance liquid chromatography; orselective absorption on, or reaction with, a solid medium comprised of,but not limited to, any one or any combination of the following solidmedia: ion-exchange resin; a solid medium functionalized with amaleimide moiety; a solid medium functionalized with a reactivedisulfide; a solid medium functionalized with a chelated metal ion; or asolid medium containing an immobilized protein.

In other embodiments of the invention, a thiol-containing compound, suchas, but not restricted to, thioglycolic acid, 2-mercaptoethanesulfonicacid, glutathione, cysteine, homocysteine, mercaptosuccinic acid,thioglycerol, 2-aminoethanethiol, a dithiol such as, but not restrictedto, ethanedithiol, dithiothreitol, reduced lipoic acid (where it isdesirable to form a mercapto-thiol-Michael adduct), or thiol-containingcompound immobilized on a solid support, is used (depending on theproperties of the composition of interest and the Michael acceptor) toform a thiol-Michael adduct that can be efficiently removed from thecomposition of interest. Solid supports containing an immobilized thiolare commonly used to sequester heavy metal ions and are commerciallyavailable. Thiol functionalized solid media also can be obtained byreaction of a solid support containing an immobilizedN-hydroxysuccinimide ester or p-nitrophenyl ester or other aminereactive ester with an aminothiol, such as, but not limited to,glutathione, 2-aminoethanethiol, or cysteine, or by reacting solidmedium functionalized with an organic halide or a maleimide with adithiol, such as, but not limited to, ethanedithiol, or reduced lipoicacid.

It is important to note that selection of the most suitable thiol for aprocess may require a detailed cost analysis of the process that takesinto account the observations that certain soluble thiol-containingcompounds may allow shorter manufacturing cycle times, may be lesscostly, and may enable facile determination of Michael acceptor levels,whereas certain thiol functionalized solid media may provide moreconvenient removal of the thiol-Michael adduct.

Certain embodiments of the present invention involve removal of aMichael acceptor from a composition comprised of an organic base, suchas oxycodone, whose solubility in water decreases with increasing pH.Such embodiments may involve treatment of the composition of interestwith a suitable soluble thiol-containing compound such as, but notrestricted to, sodium thioglycolate, cysteine hydrochloride, sodium2-mercaptoethanesulfonate, 5-mercapto-2-nitro-benzoic acid, orN-dansylcysteine, and formation (in aqueous solution at a suitable pH)of a soluble thiol-Michael adduct. The organic base of interest may beprecipitated from the solution of soluble thiol-Michael adduct andexcess thiol-containing compound by raising the pH to a suitable value.Further unit operations may be required to remove co-precipitatedthiol-Michael adduct from the precipitated composition.

Other embodiments of the present invention involve removal of a Michaelacceptor from a composition, such as an organic acid, whose solubilityin water decreases with decreasing pH. Such embodiments may involvetreatment of the composition of interest with a suitable solublethiol-containing compound, such as, but not restricted to, cysteinehydrochloride, sodium 2-mercaptoethanesulfonate, or 2-aminoethanethiol,and formation (in aqueous solution at a suitable pH) of a solublethiol-Michael adduct. The organic composition of interest may beprecipitated from the solution of soluble thiol-Michael adduct andexcess thiol-containing compound by lowering the pH to a suitable value.Further unit operations may be required to remove co-precipitatedthiol-Michael adduct from the precipitated composition.

Other embodiments of the present invention may involve removal ofcontaminating Michael acceptor wherein it is desirable to carry out thereaction in a non-aqueous solvent because the composition of interesthas a poor solubility in water.

Such cases may involve treatment of the composition of interest with asuitable thiol such that the thiol and/or thiol-Michael adduct can beremoved from the composition of interest. A thiol, such as, but notlimited to, 2-aminoethanethiol, could be a suitable thiol for theseembodiments of the present invention since 2-aminoethanethiol could forma thiol-Michael adduct that could be extracted into aqueous acid and,thereby, removed from a water insoluble composition of interest. Furtherunit operations may be required to remove co-precipitated thiol-Michaeladduct from the precipitated composition of interest.

Still other embodiments of the present invention include the detectionand removal of a Michael acceptor hydrate. Removal of this Michaelacceptor precursor from a composition may be desirable in cases whereinits conversion to a Michael acceptor is significant. Certain embodimentsof the present invention include conversion of the Michael acceptorhydrate to a Michael acceptor by treatment with an acidic catalyst andsubsequent removal and/or quantification of the Michael acceptor via itsconversion to a thiol-Michael adduct using the teachings of the presentinvention.

The appended examples illustrate application of processes of the presentinvention for reducing Michael acceptor levels in oxycodone and relatedcompositions and/or quantifying Michael acceptor levels in oxycodone andrelated compositions.

The appended examples, together with the other teachings herein,including the appended claims, enable one skilled in the art to applyembodiments of the present invention to cases not specificallyillustrated by an example. These additional embodiments of the presentinvention include, but are not limited to, cases wherein:

The Michael acceptor and the composition of interest are chosen from,but not limited to, one or more of the following examples:

i. The Michael acceptor is acrylonitrile; and the composition ofinterest is produced via a process utilizing acrylonitrile, and isselected from, but not restricted to, one or more of the followingcompositions: styrene-acrylonitrile; andacrylonitrile-butadiene-styrene; and acrylonitrile-methyl methacrylatepolymers.

ii. The Michael acceptor is acrylamide; and the composition of interestis produced via a process utilizing acrylamide, and is selected from,but not restricted to, one or more of the following compositions:polyacrylamide and copolymers thereof.

iii. The Michael acceptor is methyl acrylate; and the composition ofinterest is produced via a process utilizing methyl acrylate, and isselected from, but not restricted to, one or more of the followingcompositions: Vitamin B1; poly(methyl acrylate) and copolymers thereof.

iv. The Michael acceptor is ethyl acrylate; and the composition ofinterest is produced via a process utilizing ethyl acrylate, and isselected from, but not restricted to, one or more followingcompositions: poly(ethyl acrylate) and copolymers thereof.

v. The Michael acceptor is methyl methacrylate; and the composition ofinterest is produced via a process utilizing methyl methacrylate, and isselected from, but not restricted to, one or more of the followingcompositions: poly(methyl methacrylate) and copolymers thereof.

vi. The Michael acceptor is 2-ethylhexyl acrylate; and the compositionof interest is produced via a process utilizing 2-ethyl acrylate, and isselected from, but not restricted to, one or more of the followingcompositions: poly(2-ethylhexyl acrylate) and copolymers thereof.

vii. The Michael acceptor is crotonaldehyde; and the composition ofinterest is produced via a process utilizing crotonaldehyde, and isselected from, but not restricted to, one or more of the followingcompositions: 2-ethylhexyl alcohol; butyraldehyde and quinaldine.

viii. The Michael acceptor is methyl vinyl ketone; and the compositionof interest is produced via a process utilizing methyl vinyl ketone, andmay be selected, but not restricted to, Vitamin A.

ix. The Michael acceptor is acrolein; and the composition of interest iscigarette, cigar, or pipe smoke.

Unless specified otherwise, all operations in the following exampleswere carried out at room temperature.

EXAMPLE 1A Removal of 14-hydroxycodeinone from an Oxycodone Composition

This example describes treatment of an oxycodone free base compositioncontaining more than 300 ppm but less than 1000 ppm of14-hydroxycodeinone with 20 mM sodium thioglycolate at pH 6 to effect(together with other operations) removal of 14-hydroxycodeinone and thethiol-Michael adduct, and produce a processed product containing lessthan 10 ppm of 14-hydroxycodeinone.

An oxycodone sample containing more than 300 ppm of 14-hydroxycodeinonewas dissolved in water at pH 6.0 to produce a 7.5% solution (75 mg/mL)using 4 M HCl to effect neutralization and dissolution of the oxycodoneto pH 6. Sufficient solid EDTA and solid sodium thioglycolate were addedto bring the concentrations of these components in the reaction mixtureto 2 mM EDTA and 20 mM thioglycolate. The pH was maintained at pH 6.0,at room temperature for 2.8 hours, after which time the reaction mixturewas raised to pH 9 to precipitate the oxycodone from the solutioncontaining the thioglycolate-Michael adduct, and excess thioglycolate.The precipitated oxycodone was washed with pH 9, 0.05 M sodiumbicarbonate buffer, and dissolved in ethyl acetate. The ethyl acetatesolution of oxycodone was extracted with pH 9.0, 0.05 M sodiumbicarbonate buffer, and the ethyl acetate removed under reduced pressureto yield oxycodone containing less than 10 ppm of 14-hydroxycodeinone.

EXAMPLE 1B Removal of 14-hydroxycodeinone from an Oxycodone Compositionwith 20 mM Sodium Thioglycolate

This example describes treatment of an oxycodone free base compositioncontaining 3525 ppm of 14-hydroxycodeinone with 20 mM sodiumthioglycolate to effect (together with other operations) a more than800-fold reduction in 14-hydroxycodeinone content of the composition andproduce a product wherein the sum of the 14-hydroxycodeinone and the2-(oxycodone-8-sulfanyl)-acetic acid content was less than 5 ppm.

Oxycodone (5.0 g, 15.9 mmol) containing 3525 ppm of 14-hydroxycodeinonewas dissolved in 50 mL of 0.33 N HCl. The pH of the resulting solutionwas raised to 6.1-6.2 by addition of 1 M sodium carbonate with stirring.After dissolution of any oxycodone that precipitated during the additionof the sodium carbonate, sodium thioglycolate, chosen as athiol-containing compound (0.114 g, 1 mmol) was added. The resultingsolution was stirred for 1 h and then solid sodium carbonate (1.5 g,14.2 mmol) was added to the solution with vigorous stirring. After ˜6min (the pH of the solution increased to approximately 7.6), theoxycodone suspension was extracted into ethyl acetate (250 mL), and theethyl acetate extract was vigorously stirred with 50 mL of aqueous 20 mMsodium thioglycolate for 20 min. After separation of the sodiumthioglycolate wash, the ethyl acetate solution of oxycodone was washedwith 50 mL of water and stirred with 50 mL of 0.33 N HCl for 30 min toextract the oxycodone into the aqueous acid. The aqueous layer wasseparated and the pH was raised to 9.1-9.3 with 1 M sodium carbonate(˜22 mL) to precipitate oxycodone free base. The precipitate wascollected, washed with 25 mL of water, and dried in a desiccator underreduced pressure to yield 4.7 g (94% yield) of an oxycodone product,wherein the sum of the 14-hydroxycodeinone and the2-(oxycodone-8-sulfanyl)-acetic acid (thiol-Michael adduct) content wasless than 5 ppm (see EXAMPLES 2-3).

EXAMPLE 2 Determination of the Sum of 14-hydroxycodeinone Content andthe 2-(oxycodone-8-sulfanyl)-acetic Acid Content of the OxycodoneProduct of Example 1B

The oxycodone product of EXAMPLE 1B (0.5 g, 1.6 mmol) was dissolved in0.2 N HCl (10 mL). Ethylenediamineteraacetic acid (EDTA) (0.005 g, 0.017mmol) was added and the solution pH was raised to 6.1-6.2 with 1 Msodium carbonate with stirring to dissolve any precipitated oxycodone.To the homogeneous reaction mixture was added sodium thioglycolate(0.025 g, 0.22 mmol). In separate spike experiments known amounts of14-hydroxycodeinone were introduced prior to addition of sodiumthioglycolate. After 1.5 h, the pH of the solution was raised to 8.2-8.4with 1 M sodium carbonate (˜1.6 mL) and the suspension was extractedwith dichloromethane (2×15 mL) in a 30 mL separatory funnel. The aqueouslayer was separated and acidified with 1 N HCl (1.7 mL) to pH 2.6-3.6.An aliquot (2 mL) of the predetermined volume of the aqueous -solution(15-16 mL) was evaporated to dryness under reduced pressure on a rotaryevaporator at 30-40° C. and the residue was dissolved in 0.07%trifluoroacetic acid/water (200 uL). An aliquot of the solution wasanalyzed by HPLC, wherein an analyte in the effluent stream wasquantified from its absorbance at 280 nm. The sum of the14-hydroxycodeinone content and 2-(oxycodone-8-sulfanyl)-acetic acidcontent was 4.3 ppm as calculated from a plot of the area under the2-(oxycodone-8-sulfanyl)-acetic acid peak per milligram of oxycodoneanalyzed versus the amount of 14-hydroxycodeinone added (ppm, i.e.micrograms of 14-hydroxycodeinone added per gram of oxycodone) as shownin FIG. 1.

Plotted on the ordinate is the ratio of the area obtained for the peakcorresponding to the thiol-Michael adduct2-(oxycodone-8-sulfanyl)-acetic acid (14-HCA) and the weight ofoxycodone (Oxy) analyzed (Area Units (AU)/mg). Plotted on the abscissais the ratio of the weight of the 14-hydroxycodeinone (14-HC) spike andthe weight of oxycodone analyzed (ppm).

EXAMPLE 3 Determination of the 2-(oxycodone-8-sulfanyl)-acetic AcidContent of the Oxycodone Product of Example 1B

The oxycodone product of EXAMPLE 1B (0.51 g, 1.6 mmol) was dissolved indichloromethane (3 mL) and the solution was extracted with water (3 mL).An aliquot (1 mL) of the aqueous extract was acidified with 1 N HCl (10uL) and evaporated to dryness under reduced pressure on a rotaryevaporator at 30-40° C. The residue was dissolved in 0.07%trifluoroacetic acid/water (200 uL) and an aliquot of the solution wasanalyzed by HPLC, wherein an analyte in the effluent stream wasquantified from its absorbance at 280 nm. The content of2-(oxycodone-8-sulfanyl)-acetic acid in the sample was equal to or lessthan 0.1 ppm.

EXAMPLE 4 Determination of the 14-hydroxycodeinone Content of theOxycodone Product of Example 1B

The 14-hydroxycodeinone content was determined by subtracting the2-(oxycodone-8-sulfanyl)-acetic acid content of the oxycodone product asdetermined in EXAMPLE 3 from the sum of the 14-hydroxycodeinone contentand the 2-(oxycodone-8-sulfanyl)-acetic acid content of the oxycodoneproduct as determined in EXAMPLE 2. Thus, the 14-hydroxycodeinonecontent of the oxycodone product of EXAMPLE 1 was ≦4.3 ppm.

EXAMPLE 5 Removal of 14-hydroxycodeinone from an Oxycodone Compositionwith 20 mM Sodium 2-mercaptoethanesulfonate

This example describes treatment of an oxycodone free base compositioncontaining 3525 ppm of 14-hydroxycodeinone with 20 mM sodium2-mercaptoethanesulfonate to effect (together with other operations) amore than 300-fold reduction in 14-hydroxycodeinone content of thecomposition and produce a product wherein the sum of the14-hydroxycodeinone and the 2-(oxycodone-8-sulfanyl)-ethanesulfonic acidcontent was less than 15 ppm.

Oxycodone (5.0 g, 15.9 mmol) containing 3525 ppm of 14-hydroxycodeinonewas dissolved in 50 mL of 0.33 N HCl. The pH of the resulting solutionwas raised to 6.1-6.2 by addition of 1 M sodium carbonate with stirring.After dissolution of any oxycodone that precipitated during the additionof the sodium carbonate, sodium 2-mercaptoethanesulfonate (0.165 g, 1mmol) was added, the resulting solution stirred for 1 h and solid sodiumcarbonate (1.5 g, 14.2 mmol) then added to the solution with vigorousstirring. After ˜6 min (the pH of the solution increased toapproximately 7.6), the oxycodone suspension was extracted into ethylacetate (250 mL), and the ethyl acetate extract was vigorously stirredwith 50 mL of aqueous 20 mM sodium 2-mercaptoethanesulfonate solutionfor 20 min. After removal of the sodium 2-mercaptoethanesulfonate wash,the ethyl acetate solution of oxycodone was washed with 50 mL of waterand stirred with 50 mL of 0.33 N HCl for 10 min to extract the oxycodoneinto the aqueous acid. The aqueous layer was separated and the pH wasraised to 9.2-9.4 with 1 M sodium carbonate (˜22 mL) to precipitateoxycodone free base. The precipitate was collected, washed with 25 mL ofwater, and dried in a desiccator under reduced pressure to yield 4.7 g(94% yield) of an oxycodone product; wherein the sum of the14-hydroxycodeinone content and the2-(oxycodone-8-sulfanyl)-ethanesulfonic acid content was less than 15ppm (see EXAMPLES 6-7).

EXAMPLE 6 Determination of the 14-hydroxycodeinone Content of theOxycodone Product of Example 5

The oxycodone product of EXAMPLE 5 (0.5 g, 1.6 mmol) was dissolved in0.2 N HCl (10 mL). EDTA (0.005 g, 0.017 mmol) was added and the solutionpH was raised to 6.1-6.2 with 1 M sodium carbonate with stirring todissolve any precipitated oxycodone. To the homogeneous reaction mixturewas added sodium thioglycolate (0.025 g, 0.22 mmol). In separate spikeexperiments known amounts of 14-hydroxycodeinone were introduced priorto addition of sodium thioglycolate. After 1.5 h the pH of the solutionwas raised to 8.2-8.4 with 1 M sodium carbonate (˜1.6 mL) and thesuspension was extracted with dichloromethane (2×15 mL) in a 30 mLseparatory funnel. The aqueous layer was separated and acidified with 1N HCl (1.7 mL) to pH 2.6-3.6. An aliquot (2 mL) of the predeterminedvolume of the aqueous solution (15-16 mL) was evaporated to drynessunder reduced pressure on a rotary evaporator at 30-40° C. and theresidue dissolved in 0.07% trifluoroacetic acid/water (200 uL). Analiquot of the solution was analyzed by HPLC, wherein an analyte in theeffluent stream was quantified from its absorbance at 280 nm. The14-hydroxycodeinone content of the sample was 8.7 ppm as determined froma plot of the area under the 2-(oxycodone-8-sulfanyl)-acetic acid peakper milligram of oxycodone analyzed versus the amount of14-hydroxycodeinone added (ppm, i.e. micrograms of 14-hydroxycodeinoneadded per gram of oxycodone) as shown in FIG. 2. Control experimentsindicated that the conversion of the thiol-Michael adduct contained inthe analyte of this example (2-(oxycodone-8-sulfanyl)-ethanesulfonicacid) and contained in the analytes of other examples described herein,to the corresponding to the 2-(oxycodone-8-sulfanyl)-acetic acidthiol-Michael adduct during analytic determinations using sodiumthioglycolate was negligible (<15%).

Plotted on the ordinate is the ratio of the area obtained for the peakcorresponding to the thiol-Michael adduct2-(oxycodone-8-sulfanyl)-acetic acid (14-HCA) and the weight ofoxycodone (Oxy) analyzed (Area Units (AU)/mg). Plotted on the abscissais the ratio of the weight of the 14-hydroxycodeinone (14-HC) spike andthe weight of oxycodone analyzed (ppm).

EXAMPLE 7 Determination of the 2-(oxycodone-8-sulfanyl)-ethanesulfonicAcid Content of the Oxycodone Product of Example 5

The oxycodone product of EXAMPLE 5 (0.5 g, 1.6 mmol) was dissolved indichloromethane (3 mL) and the solution was extracted once with water (3mL). An aliquot (1 mL) of the aqueous extract was acidified with 1 N HCl(10 uL) and evaporated to dryness under reduced pressure on a rotaryevaporator at 30-40° C. The residue was dissolved in 0.07%trifluoroacetic acid/water (200 uL) and the sample analyzed by HPLC,wherein an analyte in the effluent stream was quantified from itsabsorbance at 280 nm. The 2-(oxycodone-8-sulfanyl)-ethanesulfonic acidcontent of the oxycodone product produced in EXAMPLE 5 was thusdetermined to be 1.3 ppm.

EXAMPLE 8 Removal of 14-hydroxycodeinone from an Oxycodone Compositionwith 40 mM L-cysteine

This example describes treatment of an oxycodone free base compositioncontaining 3525 ppm of 14-hydroxycodeinone with 40 mM L-cysteinehydrochloride to effect (together with other operations) a more than500-fold reduction in 14-hydroxycodeinone content of the composition andproduce a product wherein the sum of the 14-hydroxycodeinone and the2-(R)-amino-3-(oxycodone-8-sulfanyl)-propionic acid content was lessthan 10 ppm.

Oxycodone (5.0 g, 15.9 mmol) containing 3525 ppm of 14-hydroxycodeinoneand L-cysteine hydrochloride hydrate (0.352 g, 2 mmol), chosen as athiol-containing compound, were dissolved in 50 mL of 0.33 N HCl. The pHof the resulting solution was raised to 6.0-6.1 by addition of 1 Msodium carbonate with stirring to dissolve any precipitated oxycodone.The resulting solution was stirred for 1 h and then solid sodiumcarbonate (1.6 g, 15.1 mmol) was added to the solution with vigorousstirring. After ˜7 min (the pH of the solution increased toapproximately 7.6), the oxycodone suspension was extracted into ethylacetate (250 mL), and the ethyl acetate extract was vigorously stirredwith 50 mL of aqueous 40 mM L-cysteine (pH 8.0) for 45 min. Afterremoval of the L-cysteine wash, the ethyl acetate solution of oxycodonewas washed with 50 mL of water and stirred with 50 mL of 0.33 N HCl for10 min to extract the oxycodone into the aqueous acid. The aqueous layerwas separated and the pH was raised to 9.1-9.3 with 1 M sodium carbonate(˜22 mL) to precipitate oxycodone free base. The precipitate wascollected, washed with 25 mL of water, and dried in a desiccator underreduced pressure to yield 4.65 g (93% yield) of an oxycodone product,wherein the sum of the 14-hydroxycodeinone and the2-(R)-amino-3-(oxycodone-8-sulfanyl)-propionic acid (thiol-Michaeladduct) content was less than 5 ppm (see EXAMPLES 9-10).

EXAMPLE 9 Determination of the 14-hydroxycodeinone Content of theOxycodone Product of Example 8

The oxycodone product of EXAMPLE 8 (0.5 g, 1.6 mmol) was dissolved in0.2 N HCl (10 mL). EDTA (0.005 g, 0.017 mmol) was added and the solutionpH was raised to 6.0-6.3 with 1 M sodium carbonate with stirring todissolve any precipitated oxycodone. To the homogeneous reaction mixturewas added sodium thioglycolate (0.025 g, 0.22 mmol). In separate spikeexperiments known amounts of 14-hydroxycodeinone were introduced priorto addition of sodium thioglycolate. After 1 h the pH of the solutionwas raised to 8.1-8.6 with 1 M sodium carbonate (˜1.4-1.5 mL) and thesuspension was extracted with dichloromethane (2×15 mL) in a 30 mLseparatory funnel. The aqueous layer was separated and acidified with 1N HCl (1.5-1.7 mL) to pH 3.2-3.8. An aliquot (2 mL) of the predeterminedvolume of the aqueous solution (14 mL) was evaporated to dryness underreduced pressure on a rotary evaporator at 30-40° C. and the residuedissolved in 0.07% trifluoroacetic acid/water (400 uL). An aliquot ofthe solution was analyzed by HPLC, wherein an analyte in the effluentstream was quantified from its absorbance at 280 nm. The14-hydroxycodeinone content of the sample was 3.0 ppm as determined froma plot of the area under the 2-(oxycodone-8-sulfanyl)-acetic acid peakper milligram of oxycodone analyzed versus the amount of14-hydroxycodeinone added (ppm, i.e. micrograms of 14-hydroxycodeinoneadded per gram of oxycodone) as shown in FIG. 3.

Plotted on the ordinate is the ratio of the area obtained for the peakcorresponding to the thiol-Michael adduct2-(oxycodone-8-sulfanyl)-acetic acid (14-HCA) and the weight ofoxycodone (Oxy) analyzed (Area Units (AU)/mg). Plotted on the abscissais the ratio of the weight of the 14-hydroxycodeinone (14-HC) spike andthe weight of oxycodone analyzed (ppm).

EXAMPLE 10 Determination of the2-(R)-amino-3-(oxycodone-8-sulfanyl)-propionic Acid Content of theOxycodone Product of Example 8

The oxycodone product of EXAMPLE 8 (0.5 g, 1.6 mmol) was dissolved indichloromethane (3 mL) and the solution was extracted once with water (3mL). An aliquot (1 mL) of the aqueous extract was acidified with 1 N HCl(10 uL) and evaporated to dryness under reduced pressure on a rotaryevaporator at 30-40° C. The residue was dissolved in 0.07%trifluoroacetic acid/water (200 uL) and the sample analyzed by HPLC,wherein an analyte in the effluent stream was quantified from itsabsorbance at 280 nm. The 2-(R)-amino-3-(oxycodone-8-sulfanyl)-propionicacid content of the oxycodone product produced in EXAMPLE 8 was thusdetermined to be 1.6 ppm.

EXAMPLE 11 Removal of 14-hydroxycodeinone Content from an OxycodoneComposition with Thiol Functionalized Silica Gel

This example describes treatment of an oxycodone free base compositioncontaining 3525 ppm of 14-hydroxycodeinone with a commercially availablethiol functionalized silica (wherein a 3-mercaptopropanol moiety hasbeen covalently linked to silica) to effect (together with otheroperations) a more than 500-fold reduction in 14-hydroxycodeinonecontent of the composition and produce a product wherein the14-hydroxycodeinone content was less than 5 ppm.

Oxycodone (2.0 g, 6.3 mmol) containing 3535 ppm of 14-hydroxycodeinonewas dissolved in 80 mL of 0.08 N HCl. The pH of the resulting solutionwas raised to 7.0-7.05 by addition of 2 N sodium hydroxide withstirring. After dissolution of any oxycodone that precipitated duringthe addition of sodium hydroxide, thiol functionalized silica gel, (1 g,loading-1.44 mmol/g) used as the thiol-containing compound (1 g,loading-1.44 mmol/g) was added. The resulting solution was stirred for17.5 h and then filtered. The pH of the aqueous layer was raised to 9.2with 1 M sodium carbonate (˜7 mL) to precipitate oxycodone free base.The precipitate was collected, washed with 10 mL of water, and dried ina desiccator under reduced pressure to yield 1.89 g (94.5% yield) of anoxycodone product, wherein the 14-hydroxycodeinone content was less than5 ppm (see EXAMPLE 12).

EXAMPLE 12 Determination of the 14-hydroxycodeinone Content of theOxycodone Product of Example 11

The oxycodone product of EXAMPLE 11 (0.5 g, 1.6 mmol) was dissolved in0.2 N HCl (10 mL). EDTA (0.005 g, 0.017 mmol) was added and the solutionpH was raised to 6.0-6.2 with 1 M sodium carbonate with stirring todissolve any precipitated oxycodone. To the homogeneous reaction mixturewas added sodium thioglycolate (0.025 g, 0.22 mmol). In separate spikeexperiments known amounts of 14-hydroxycodeinone were introduced priorto addition of sodium thioglycolate. After 1 h, the pH of the solutionwas raised to 8.0-8.3 with 1 M sodium carbonate (˜1.5-1.6 mL) and thesuspension was extracted with dichloromethane (2×15 mL) in a 30 mLseparatory funnel. The aqueous layer was separated and acidified with 1N HCl (1.6-1.7 mL) to pH 2.5-3.4. An aliquot (2 mL) of the predeterminedvolume of the aqueous solution (15 mL) was evaporated to dryness underreduced pressure on a rotary evaporator at 30-40° C. and the residuedissolved in 0.07% trifluoroacetic acid/water (400 uL). An aliquot ofthe solution was analyzed by HPLC, wherein an analyte in the effluentstream was quantified from its absorbance at 280 nm. The14-hydroxycodeinone content of the sample was 3.4 ppm as determined froma plot of the area under the 2-(oxycodone-8-sulfanyl)-acetic acid peakper milligram of oxycodone analyzed versus the amount of14-hydroxycodeinone added (ppm, i.e. micrograms of 14-hydroxycodeinoneadded per gram of oxycodone) as shown in FIG. 4.

Plotted on the ordinate was the ratio of the area obtained for the peakcorresponding to the thiol-Michael adduct2-(oxycodone-8-sulfanyl)-acetic acid (14-HCA) and the weight ofoxycodone (Oxy) analyzed (Area Units (AU)/mg). Plotted on the abscissais the ratio of the weight of the 14-hydroxycodeinone (14-HC) spike andthe weight of oxycodone analyzed (ppm).

EXAMPLE 13 Removal of 14-hydroxycodeinone of an Oxycodone Compositionwith 20 mM N-acetyl-L-cysteine

This example describes treatment of an oxycodone free base compositioncontaining 3525 ppm of 14-hydroxycodeinone with 20 mMN-acetyl-L-cysteine to effect (together with other operations) a morethan 500-fold reduction in 14-hydroxycodeinone content of thecomposition and produce a product wherein the 14-hydroxycodeinonecontent was less than 5 ppm.

Oxycodone (5.0 g, 15.9 mmol) containing 3525 ppm of 14-hydroxycodeinoneand N-acetyl-L-cysteine, a thiol-containing compound, (0.163 g, 1 mmol)were dissolved in 50 mL of 0.32 N HCl. The pH of the resulting solutionwas raised to 6.0-6.1 by addition of 1 M sodium carbonate with stirringto dissolve any precipitated oxycodone. The resulting solution wasstirred for 1 h and then solid sodium carbonate (1.6 g, 15.1 mmol) wasadded to the solution with vigorous stirring. After ˜6 min (the pH ofthe solution increased to approximately 8.0), the oxycodone suspensionwas extracted into ethyl acetate (250 mL), and the ethyl acetate extractwas vigorously stirred with 50 mL of aqueous 20 mM N-acetyl-L-cysteine(pH 8.0) for 20 min. After removal of the N-acetyl-L-cysteine wash, theethyl acetate solution of oxycodone was washed with 50 mL of water andstirred with 50 mL of 0.34 N HCl for 10 min to extract the oxycodoneinto the aqueous acid. The aqueous layer was separated and the pH wasraised to 9.1-9.2 with 1 M sodium carbonate (˜22 mL) to precipitateoxycodone free base. The precipitate was collected, washed with 25 mL ofwater, and dried in a desiccator under reduced pressure to yield 4.7 g(94% yield) of an oxycodone product, wherein the 14-hydroxycodeinone(thiol-Michael adduct) content was less than 5 ppm (see EXAMPLE 14).

EXAMPLE 14 Determination of the 14-hydroxycodeinone Content of theOxycodone Product of Example 13

The oxycodone product of EXAMPLE 13 (0.5 g, 1.6 mmol) was dissolved in0.2 N HCl (10 mL). EDTA (0.005 g, 0.017 mmol) was added and the solutionpH was raised to 6.0-6.2 with 1 M sodium carbonate with stirring todissolve any precipitated oxycodone. To the homogeneous reaction mixturewas added sodium thioglycolate (0.025 g, 0.22 mmol). In separate spikeexperiments known amounts of 14-hydroxycodeinone were introduced priorto addition of sodium thioglycolate. After 1 h, the pH of the solutionwas raised to 8.2 with 1 M sodium carbonate (˜1.5 mL) and the suspensionwas extracted with dichloromethane (2×15 mL) in a 30 mL separatoryfunnel. The aqueous layer was separated and acidified with 1 N HCl (1.6mL) to pH 3.5-3.7. An aliquot (2 mL) of the predetermined volume of theaqueous solution (15-16 mL) was evaporated to dryness under reducedpressure on a rotary evaporator at 30-40° C. and the residue dissolvedin 0.07% trifluoroacetic acid/water (400 uL). An aliquot of the solutionwas analyzed by HPLC, wherein an analyte in the effluent stream wasquantified from its absorbance at 280 nm. The 14-hydroxycodeinonecontent of the sample was 4.6 ppm as determined from a plot of the areaunder the 2-(oxycodone-8-sulfanyl)-acetic acid peak per milligram ofoxycodone analyzed versus the amount of 14-hydroxycodeinone added (ppm,i.e. micrograms of 14-hydroxycodeinone added per gram of oxycodone) asshown in FIG. 5.

Plotted on the ordinate is the ratio of the area obtained for the peakcorresponding to the thiol-Michael adduct2-(oxycodone-8-sulfanyl)-acetic acid (14-HCA) and the weight ofoxycondone (Oxy) analyzed (Area Units (AU)/mg). Plotted on the abscissais the ratio of the weight of the 14-hydroxycodeinone (14-HC) spike andthe weight of oxycodone analyzed (ppm).

EXAMPLE 15 Removal of the 14-hydroxycodeinone from an OxycodoneComposition with 40 mM Sodium 2-mercaptoethanesulfonate

This example describes treatment of an oxycodone free base compositioncontaining 3525 ppm of 14-hydroxycodeinone with 40 mM sodium2-mercaptoethanesulfonate to effect (together with other operations) amore than 300-fold reduction in 14-hydroxycodeinone content of thecomposition and produce a product wherein the sum of the14-hydroxycodeinone and the 2-(oxycodone-8-sulfanyl)-ethanesulfonic acidcontent was less than 10 ppm.

Oxycodone (5.0 g, 15.9 mmol) containing 3525 ppm of 14-hydroxycodeinonewas dissolved in 50 mL of 0.33 N HCl. The pH of the resulting solutionwas raised to 6.2 by addition of 1 M sodium carbonate with stirring.After dissolution of any oxycodone that precipitated during the additionof the sodium carbonate, sodium 2-mercaptoethanesulfonate (0.33 g, 2mmol) was added, the resulting solution stirred for 1 h and solid sodiumcarbonate (1.5 g, 14.2 mmol) then added to the solution with vigorousstirring. After ˜6 min (the pH of the solution increased toapproximately 7.8), the oxycodone suspension was extracted into ethylacetate (250 mL), and the ethyl acetate extract was vigorously stirredwith 50 mL of the aqueous 20 mM sodium 2-mercaptoethanesulfonatesolution for 20 min. After removal of the sodium2-mercaptoethanesulfonate wash, the ethyl acetate solution of oxycodonewas washed with 50 mL of water and stirred with 50 mL of 0.34 N HCl for10 min to extract the oxycodone into the aqueous acid. The aqueous layerwas separated and the pH was raised to 9.2-9.3 with 1 M sodium carbonate(˜22 mL) to precipitate oxycodone free base. The precipitate wascollected, washed with 25 mL of water, and dried in a desiccator underreduced pressure to yield 4.66 g (93.2% yield) of an oxycodone product,the sum of the 14-hydroxycodeinone content and the2-(oxycodone-8-sulfanyl)-ethanesulfonic acid content was less than 10ppm (see EXAMPLES 16-17).

EXAMPLE 16 Determination of the 14-hydroxycodeinone content of theOxycodone Product of Example 15

The oxycodone product of EXAMPLE 15 (0.5 g, 1.6 mmol) was dissolved in0.2 N HCl (10 mL). EDTA (0.005 g, 0.017 mmol) was added and the solutionpH was raised to 6.1-6.2 with 1 M sodium carbonate with stirring todissolve any precipitated oxycodone. To the homogeneous reaction mixturewas added sodium thioglycolate (0.025 g, 0.22 mmol). In separate spikeexperiments known amounts of 14-hydroxycodeinone were introduced priorto addition of sodium thioglycolate. After 1 h, the pH of the solutionwas raised to 8.2-8.4 with 1 M sodium carbonate (˜1.5 mL) and thesuspension was extracted with dichloromethane (2×15 mL) in a 30 mLseparatory funnel. The aqueous layer was separated and acidified with 1N HCl (1.6 mL) to pH 3.2-3.5. An aliquot (2 mL) of the predeterminedvolume of the aqueous solution (14.5-16 mL) was evaporated to drynessunder reduced pressure on a rotary evaporator at 30-40° C. and theresidue dissolved in 0.07% trifluoroacetic acid/water (400 uL). Analiquot of the solution was analyzed by HPLC, wherein an analyte in theeffluent stream was quantified from its absorbance at 280 nm. The14-hydroxycodeinone content of the sample was 6.0 ppm as determined froma plot of the area under the 2-(oxycodone-8-sulfanyl)-acetic acid peakper milligram of oxycodone analyzed versus the amount of14-hydroxycodeinone added (ppm, i.e. micrograms of 14-hydroxycodeinoneadded per gram of oxycodone) as shown FIG. 6.

Plotted on the ordinate is the ratio of the area obtained for the peakcorresponding to the thiol-Michael adduct2-(oxycodone-8-sulfanyl)-acetic acid (14-HCA) and the weight ofoxycodone (Oxy) analyzed (Area Units (AU)/mg). Plotted on the abscissais the ratio of the weight of the 14-hydroxycodeinone (14-HC) spike andthe weight of oxycodone analyzed (ppm)

EXAMPLE 17 Determination of the 2-(oxycodone-8-sulfanyl)-ethanesulfonicAcid Content of the Oxycodone Product of Example 15

The oxycodone product of EXAMPLE 15 (0.5 g, 1.6 mmol) was dissolved indichloromethane (3 mL) and the solution was extracted once with water (3mL). An aliquot (1 mL) of the aqueous extract was acidified with 1 N HCl(10 uL) and evaporated to dryness under reduced pressure on a rotaryevaporator at 30-40° C. The residue was dissolved in 0.07%trifluoroacetic acid/water (200 uL) and the sample analyzed by HPLC,wherein an analyte in the effluent stream was quantified from itsabsorbance at 280 nm. The 2-(oxycodone-8-sulfanyl)-ethanesulfonic acidcontent of the oxycodone product produced in EXAMPLE 15 was thusdetermined to be 1.6 ppm.

EXAMPLE 18 Reduction of the 7,8-dehydronaltrexone Content of Naltrexone

This example describes the reduction of the 7,8-dehydronaltrexonecontent of naltrexone by more than 300-fold and production of analtrexone product wherein the 7,8-dehydronaltrexone content was lessthan 5 ppm by treatment of naltrexone in water with sodiumthioglycolate.

Naltrexone (2.0 g, 5.9 mmol) containing 690 ppm of 7,8-dehydronaltrexonewas dissolved in 20 mL of 0.3 N HCl. The pH of the resulting solutionwas raised to 6.15 by addition of 1 M sodium carbonate with stirring.After dissolution of any naltrexone that precipitated during theaddition of sodium carbonate, sodium thioglycolate (0.046 g, 0.4 mmol)was added. The resulting solution was stirred for 1 h and then solidsodium carbonate (0.6 g, 5.7 mmol) was added to the solution withvigorous stirring. After ˜8 min (the pH of the solution increased toapproximately 8.1-8.2), the naltrexone suspension was extracted intoethyl acetate (100 mL), and the ethyl acetate extract was vigorouslystirred with 20 mL of aqueous 20 mM sodium thioglycolate for 20 min.After removal of the sodium thioglycolate wash, the ethyl acetatesolution of naltrexone was washed with 20 mL of water and stirred with20 mL of 0.34 N HCl for 10 min to extract naltrexone into the aqueousacid. The aqueous layer was separated and the pH was raised to 8.8-8.9with 1 M sodium carbonate (˜7.5 mL) to precipitate naltrexone. Theprecipitate was collected, washed with 4 mL of water, and dried in adesiccator under reduced pressure to yield 1.95 g (97.5% yield) of analtrexone product, wherein the 7,8-dehydronaltrexone content was lessthan 5 ppm (see EXAMPLE 19).

EXAMPLE 19 Determination of the 7,8-dehydronaltrexone Content of theNaltrexone Product of Example 18

The naltrexone product of EXAMPLE 18 (0.5 g, 1.47 mmol) was dissolved in0.2 N HCl (10 mL). EDTA (0.005 g, 0.017 mmol) was added and the solutionpH was raised to 6.0 with 1 M sodium carbonate with stirring to dissolveany precipitated naltrexone. To the homogeneous reaction mixture wasadded sodium thioglycolate (0.025 g, 0.22 mmol). After 1 h the pH of thesolution was raised to 8.9 with 1 M sodium carbonate (˜1.5 mL) and thesuspension was extracted with dichloromethane (2×15 mL) in a 30 mLseparatory funnel. The aqueous layer was separated and acidified with 1N HCl (1.6 mL). An aliquot (2 mL) of the predetermined volume of theaqueous solution (15-16 mL) was evaporated to dryness under reducedpressure on a rotary evaporator at 30-40° C. and the residue dissolvedin 0.07% trifluoroacetic acid/water (400 uL). An aliquot of the solutionwas analyzed by HPLC, wherein an analyte in the effluent stream wasquantified from its absorbance at 280 nm. The 7,8-dehydronaltrexonecontent was ˜1 ppm.

EXAMPLE 20 Determination of the 14-hydroxycodeinone Content of anOxycodone Product Using a Reduced Amount of Sample

The following procedure represents a modification of the proceduredescribed in EXAMPLE 14 that was designed for use when the amount ofoxycodone product available for analysis was limited. The oxycodoneproduct of EXAMPLE 13 (100 mg, 0.317 mmol) was placed in an 8 mLreaction vial, one that accommodates a threaded, Teflon-lined cap andsmall magnetic stir bar, and dissolved in 0.2 N HCl (2 mL). EDTA (0.001g, 0.0034 mmol) was added and the solution pH was raised to 6.0-6.2 byaddition of 1 M aqueous sodium carbonate with stirring to dissolve anyprecipitated oxycodone. Determination of pH was accomplished using a pHmeter with a sufficiently narrow combination electrode (˜5 mm) so as toallow its insertion directly into the sample vial. To the homogeneousreaction mixture was added sodium thioglycolate (0.005 g, 0.044 mmol);in separate spike experiments, known amounts of 14-hydroxycodeinone wereintroduced prior to addition of sodium thioglycolate. After 1 h, the pHof the solution was raised to 8.2 with 1 M aqueous sodium carbonate(˜0.07 mL) and the suspension was extracted with dichloromethane (2×3mL) by adding the solvent to the vial, capping it, and shaking itvigorously. The organic layer was removed from the vial by Pasteurpipet. The aqueous layer was acidified with 1 N HCl (0.3 mL) and thesolution reduced to dryness via rotary evaporation (bath temp 30-40°C.). The residue was dissolved in 0.07% trifluoroacetic acid/water (400uL) and an aliquot of the solution was analyzed by HPLC, wherein ananalyte in the effluent stream was quantified from its absorbance at 280nm. The 14-hydroxycodeinone content of the sample was 4.3 ppm asdetermined from a plot of the area under the2-(oxycodone-8-sulfanyl)-acetic acid peak per milligram of oxycodoneanalyzed versus the amount of 14-hydroxycodeinone added (ppm, i.e.micrograms of 14-hydroxycodeinone added per gram of oxycodone) as shownin FIG. 7. The 14-hydroxycodeinone content determined by this method(4.3 ppm) was within 10 percent of the determination made for the samesample as described in EXAMPLE 14 (4.6 ppm).

Plotted on the ordinate is the ratio of the area obtained for the peakcorresponding to the thiol-Michael adduct2-(oxycodone-8-sulfanyl)-acetic acid (14-HCA) and the weight ofoxycodone (Oxy) analyzed (Area Units (AU)/mg). Plotted on the abscissais the ratio of the weight of the 14-hydroxycodeinone (14-HC) spike andthe weight of oxycodone analyzed, in ppm.

EXAMPLE 21 Determination of the 14-hydroxycodeinone Content of theOxycodone Product of Example 13 with 5-mercapto-2-nitro-benzoic Acid

The oxycodone product of EXAMPLE 13 (0.300 g, 0.952 mmol) was suspendedin 0.2 N aqueous HCl (3 mL) in an 8 mL reaction vial—one thataccommodates a threaded, Teflon-lined cap and small magnetic stir bar.Concentrated HCl was added (30 uL), dissolving the solid completely, andthe pH was raised to 4.5 by addition of 100 mg/mL aqueous Na₂HPO₄solution (0.11 mL) and 1 N aqueous HCl (0.05 mL). Determination of pHwas accomplished using a pH meter with a sufficiently narrow combinationelectrode (˜5 mm) so as to allow its insertion directly into the samplevial. An aliquot of this solution (1 mL) was diluted with pH 4.5 0.05 Maqueous NaOAc/HOAc buffer (0.1 mL) and set aside; the remainder wasreserved for separate spike experiments where known amounts of14-hydroxycodeinone were added prior to the next step. In a separatereaction vessel, 5,5′-dithiobis(2-nitro-benzoic acid) (10 mg, 0.025mmol) was completely dissolved in pH 7 0.05 M aqueous sodium phosphatebuffer solution (5 mL). EDTA (5 mg) and dithiothreitol (2.0 mg, 0.013mmol) were added and the pH of the resulting orange-colored solution wasraised to 6.8 with 100 mg/mL aqueous Na₂HPO₄ solution (0.45 mL). Afterstirring for 30 minutes, the pH was lowered to 4.7 with 25% aqueousacetic acid solution (0.105 mL) and an aliquot of this solution (1 mL)was added to the vial containing the previously prepared oxycodonesolution. After stirring for 90 minutes, the pH of the combined solutionwas lowered to 2 with concentrated HCl (15 uL) and the resultingsuspension extracted with dichloromethane (4×2 mL) by adding the solventto the vial, capping it, and shaking vigorously. The organic layer wascompletely removed from the vial by Pasteur pipet. The aqueous layer wasanalyzed by HPLC, wherein an analyte in the effluent stream wasquantified from its absorbance at 325 nm. The 14-hydroxycodeinonecontent of the sample was 4.7 ppm as determined from a plot of the areaunder the 2-nitro-5-(oxycodone-8-sulfanyl)-benzoic acid peak permilligram of oxycodone analyzed versus the amount of 14-hydroxycodeinoneadded (ppm, i.e. micrograms of 14-hydroxycodeinone added per gramoxycodone) as shown in FIG. 8. The 14-hydroxycodeinone contentdetermined by this method (4.7 ppm) was within 10 percent of thedetermination made for the same sample as described in EXAMPLE 14 (4.6ppm).

Plotted on the ordinate is the ratio of the area obtained for the peakcorresponding to the thiol-Michael adduct2-nitro-(5-(oxycodone-8-sulfanyl)-benzoic acid (14-HCA) and the weightof oxycodone (Oxy) analyzed (Area Units (AU)/mg). Plotted on theabscissa is the ratio of the weight of the 14-hydroxycodeinone (14-HC)spike and the weight of oxycodone analyzed, in ppm.

EXAMPLE 22 Determination of the 14-hydroxycodeinone Content of anOxycodone Hydrochloride Composition with 5-mercapto-2-nitro-benzoic Acid

In an 8 mL reaction vial, one that accommodates a threaded, Teflon-linedcap and small magnetic stir bar, a pH 7.4 buffer was prepared bydissolving 5 mg of EDTA in 0.1 M aqueous Na₂HPO₄ solution (4.75 mL) and0.1 M aqueous NaH₂PO₄ solution (0.25 mL). Dithiothreitol (2.1 mg, 0.014mmol) was added followed by 5,5′-dithiobis(2-nitro-benzoic acid) (9.8mg, 0.025 mmol) which immediately turned the solution color orange. Whenthe solid completely dissolved (5 minutes), the pH of the solution waslowered to 4.5 with 1 N aqueous HCl solution (0.35 mL). Determination ofpH was accomplished using a pH meter with a sufficiently narrowcombination electrode (˜5 mm) so as to allow its insertion directly intothe sample vial. Oxycodone hydrochloride (482 mg, 1.37 mmol) was placedin a separate 8 mL reaction vial, to which was added 3.0 mL of thepreviously prepared solution. The pH of the mixture was lowered to 4.5by addition of 1 N aqueous HCl solution (10 uL), and a 1.0 mL aliquotwas removed and stirred. The remainder was reserved for separate spikeexperiments where known amounts of 14-hydroxycodeinone were added to themixture. After 90 minutes, the pH was lowered to 2 with concentrated HCl(10 uL) and the suspension extracted with dichloromethane (4×1 mL) byadding the solvent to the vial, capping it, and shaking vigorously. Theorganic layer was completely removed from the vial by Pasteur pipet. Theaqueous layer was analyzed by HPLC, wherein an analyte in the effluentstream was quantified from its absorbance at 325 nm. The14-hydroxycodeinone content of the sample was 46 ppm as determined froma plot of the area under the 2-nitro-5-(oxycodone-8-sulfanyl)-benzoicacid peak per milligram of oxycodone analyzed versus the amount of14-hydroxycodeinone added (ppm, i.e. micrograms of 14-hydroxycodeinoneadded per gram of oxycodone) as shown in FIG. 9.

Plotted on the ordinate is the ratio of the area obtained for the peakcorresponding to the thiol-Michael adduct5-(oxycodone-8-sulfanyl)-2-nitro-benzoic acid (14-HCA) and the weight ofoxycodone (Oxy) analyzed (Area Units (AU)/mg). Plotted on the abscissais the ratio of the weight of the 14-hydroxycodeinone (14-HC) spike andthe weight of oxycodone analyzed, in ppm.

EXAMPLE 23 Use of N-dansyl-L-cysteine to Determine the14-hydroxycodeinone Content of a Oxycodone-Hydrochloride ProcessedProduct that was Prepared by Removing 14-hydroxycodeinone (with 20 mMthioglycolate) from the Composition Analyzed in Example 22

In a 25 mL round-bottom reaction flask equipped with a magnetic stirbar, the following were added: 10 mL of a pH 7.0, 50 mM phosphatebuffer; EDTA (2 mg, 0.007 mmol); dithiothreitol (3.1 mg, 0.020 mmol);N,N′-didansyl-L-cystine (28 mg, 0.038 mmol). The pH of the resultingsolution was raised to 7.0 with 10% aqueous disodium phosphate (0.5 mL),and the solution stirred for 1 h. A 3.5 mL aliquot of the solution wasthen added to an 8 mL reaction vial containing oxycodone hydrochloride(230 mg, 0.65 mmol). The pH of the resulting oxycodone solution wasraised to 6.1-6.2 by addition of 10% aqueous disodium phosphate (0.2mL). An aliquot (1.2 mL) was removed and placed in an 8 mL reactionvial. The remainder was reserved for separate spike experiments. After90 minutes, the pH of the reaction mixture was lowered to 2.4-2.5 with 1N HCl, and the resulting solution extracted with once with ethyl acetate(1.5 mL). The aqueous phase was analyzed by HPLC wherein an analyte inthe effluent stream was quantified from its fluorescence at 530 nm. The14-hydroxycodeinone content of the sample was 0.6 ppm as determined froma plot of the area under the2-(R)-(5-dimethylamino-naphthalene-1-sulfonylamino)-3-(oxycodone-8-sulfanyl)-propionicacid peak per milligram of oxycodone analyzed versus the amount of14-hydroxycodeinone added (ppm, i.e. micrograms of 14-hydrocodeinoneadded per gram of oxycodone) as shown in FIG. 10.

Plotted on the ordinate is the ratio of the area obtained for the peakattributed to the thiol-Michael adduct2-(R)-(5-dimethylamino-naphthalene-1-sulfonylamino)-3-(oxycodone-8-sulfanyl)-propionicacid (14-HCA) and the weight of oxycodone (Oxy) analyzed (Emission Units(EU)/mg). Plotted on the abscissa is the ratio of the weight of the14-hydroxycodeinone (14-HC) spike and the weight of oxycodone analyzed,in ppm.

EXAMPLE 24 Determination of the 8-hydroxyoxycodone Content of anOxycodone Composition Containing Less Than 1 ppm of 14-hydroxycodeinone

This example describes a process for determination of the8-hydroxyoxycodone content of an oxycodone composition containing lessthan 1 ppm of 14-hydroxycodeinone wherein the Michael acceptor precursor8-hydroxyoxycodone was converted to 14-hydroxycodeinone, and the14-hydroxycodeinone content of the resulting product was determined andrelated to the 8-hydroxycodone content of the original oxycodonecomposition.

In a 500 mL round-bottom flask, equipped with a reflux condenser,oxycodone (1.50 g, 4.76 mmol) and p-toluenesulfonic acid monohydrate(1.52 g, 8.0 mmol) were dissolved in toluene (300 mL) and heated toreflux. After 2.5 hours, the toluene was removed under reduced pressureat 35-40° C. by rotary evaporation. The resulting residue was dissolvedin water (100 mL) and the pH adjusted to 9 by addition of solid sodiumcarbonate (1.25 g). The aqueous solution was extracted withdichloromethane (3×30 mL), the combined organic layers were dried overanhydrous sodium sulfate and filtered, and the solvent was removed viarotary evaporation. The resulting white solid was further dried underreduced pressure to give oxycodone (1.37 g, 91%).

Determination of the 14-hydroxycodeinone content of the oxycodoneproduct using the method described in EXAMPLE 20 indicated 85 ppm of14-hydroxycodeinone. This result together with the separatelydetermined >98% conversion of 8-hydroxyoxycodone to 14-hydroxycodeinoneunder the conditions used to effect dehydration indicates that theoriginal oxycodone composition contained ˜85 ppm of 8-hydroxyoxycodone.

EXAMPLE 25 Removal of 8-hydroxyoxycodone from an Oxycodone Composition

This example describes a process for removing 8-hydroxyoxycodone from anoxycodone composition containing ˜85 ppm of 8-hydroxyoxycodone.

An oxycodone composition containing ˜85 ppm of 8-hydroxycodone wassubjected to acid catalyzed dehydration in refluxing in toluene withp-toluenesulfonic acid as described in EXAMPLE 24. A sample of theresulting oxycodone product (1.35 g, 4.29 mmol), and EDTA (15 mg) weredissolved in 0.2 N aqueous HCl (27 mL), and the pH raised to 6.1 with 1M aqueous Na₂CO₃ solution. The solution was stirred until the smallamount of oxycodone precipitate had dissolved, after which sodiumthioglycolate (68.3 mg, 0.60 mmol) was added. After stirring anadditional 60 minutes, the pH was raised to 8.1 with 1 M aqueous Na₂CO₃(4.4 mL), and the resulting white precipitate extracted intodichloromethane (3×40 mL). The combined organic extracts were dried overanhydrous sodium sulfate and filtered, and the solvent removed by rotaryevaporation to yield an oxycodone product wherein the sum of the8-hydroxyoxycodone content and the 14-hydroxycodone was less than 5 ppm(see determination in EXAMPLE 26).

EXAMPLE 26 Determination of the Sum of 8-hydroxyoxycodone and14-hydroxycodeinone Content of the Product of Example 25

A sample of the oxycodone product of EXAMPLE 25 (0.703 g, 2.23 mmol) andp-toluenesulfonic acid monohydrate (0.727 g, 3.8 mmol), and toluene (125mL) were heated to reflux in a 250 mL round-bottom flask equipped with areflux condenser. After 2.5 hours, the toluene was removed under reducedpressure at 35-40° C. by rotary evaporation. The resulting residue wasdissolved in water (50 mL) and the pH adjusted to 9 by addition of solidsodium carbonate (0.50 g). The aqueous solution was extracted withdichloromethane (3×15 mL), the combined organic layers were dried overanhydrous sodium sulfate and filtered, and the solvent removed underreduced pressure by rotary evaporation. The white solid was furtherdried under high-vacuum for 15 minutes, and dissolved in 0.1 N aqueousHCl (25 mL). The water was removed under reduced pressure at 30-35° C.by rotary evaporation and the solid dried under high-vacuum to yieldoxycodone hydrochloride.

A solution containing 5-mercapto-2-nitro-benzoic acid for use in theanalysis of the oxycodone hydrochloride was prepared using the followingprocedure. In an 8 mL reaction vial, one that accommodates a threaded,Teflon-lined cap and small magnetic stir bar, a pH 7.4 buffer wasprepared by dissolving 5 mg of EDTA in 0.1 M aqueous Na₂HPO₄ solution(4.75 mL) and 0.1 M aqueous NaH₂PO₄ solution (0.25 mL). Dithiothreitol(1.9 mg, 0.012 mmol) was added followed by5,5′-dithiobis(2-nitro-benzoic acid) (10 mg, 0.025 mmol) whichimmediately turned the solution color orange. When the solid completelydissolved (5 minutes), the pH of the solution was lowered to 4.6-4.5with 1 N aqueous HCl solution (0.285 mL). Determination of pH wasaccomplished using a pH meter with a sufficiently narrow combinationelectrode (˜5 mm) so as to allow its insertion directly into the samplevial.

A sample of the oxycodone hydrochloride (579 mg, 1.65 mmol) was placedin an 8 mL reaction vial, to which was added 3.5 ml of the previouslyprepared solution of 5-mercapto-2-nitro-benzoic acid. The pH of themixture was raised to 4.5 by addition of 100 mg/mL aqueous NaH₂PO₄solution (0.47 mL), and a 1.0 ml aliquot was removed, diluted with pH4.5, 0.01 M NaOAc/HOAc buffer solution (10 uL), and stirred. Theremainder (2.5 mL) was reserved for separate spike experiments whereknown amounts of 14-hydroxycodeinone were added to the mixture. After 90minutes, the pH was lowered to 2 with concentrated HCl (10 uL) and thesuspension extracted with ethyl acetate (3×1 mL) by adding the solventto the vial, capping it, and shaking vigorously. The organic layer wasthen completely removed from the vial by Pasteur pipet. The aqueouslayer was analyzed by HPLC, wherein an analyte in the effluent streamwas quantified from its absorbance at 325 nm. The 14-hydroxycodeinonecontent, and thus the sum of the 8-hydroxyoxycodone content and the14-hydroxycodeinone content of the product of EXAMPLE 24, was 2.3 ppm asdetermined from a plot of the area under the5-(oxycodone-8-sulfanyl)-2-nitro-benzoic acid peak per milligram ofoxycodone analyzed versus the amount of 14-hydroxycodeinone added (ppm,i.e. microrams 14-hydroxycodeinone added per gram oxycodone) as shown inFIG. 11.

Plotted on the ordinate is the ratio of the area obtained for the peakcorresponding to the thiol-Michael adduct5-(oxycodone-8-sulfanyl)-2-nitro-benzoic acid (14-HCA) and the weight ofoxycodone (Oxy) analyzed, (Area Units (AU)/mg). Plotted on the abscissais the ratio of the weight of the 14-hydroxycodeinone (14-HC) spike andthe weight of oxycodone analyzed, in ppm.

While several embodiments of the present invention have been describedand illustrated herein, those of ordinary skill in the art will readilyenvision a variety of other means and/or structures for performing thefunctions and/or obtaining the results and/or one or more of theadvantages described herein, and each of such variations and/ormodifications is deemed to be within the scope of the present invention.More generally, those skilled in the art will readily appreciate thatall parameters, dimensions, materials, and configurations describedherein are meant to be exemplary and that the actual parameters,dimensions, materials, and/or configurations will depend upon thespecific application or applications for which the teachings of thepresent invention is/are used. Those skilled in the art will recognize,or be able to ascertain using no more than routine experimentation, manyequivalents to the specific embodiments of the invention describedherein. It is, therefore, to be understood that the foregoingembodiments are presented by way of example only and that, within thescope of the appended claims and equivalents thereto, the invention maybe practiced otherwise than as specifically described and claimed. Anycombination of two or more processes, processes steps, or other featuresof the invention, if not mutually inconsistent, is included within thescope of the present invention.

The indefinite articles “a” and “an,” as used herein in thespecification and in the claims, unless clearly indicated to thecontrary, should be understood to mean “at least one.”

The phrase “and/or,” as used herein in the specification and in theclaims, should be understood to mean “either or both” of the elements soconjoined, i.e., elements that are conjunctively present in some casesand disjunctively present in other cases. Multiple elements listed with“and/or” should be construed in the same fashion, i.e., “one or more” ofthe elements so conjoined. Other elements may optionally be presentother than the elements specifically identified by the “and/or” clause,whether related or unrelated to those elements specifically identified.Thus, as a non-limiting example, a reference to “A and/or B”, when usedin conjunction with open-ended language such as “comprising” can refer,in one embodiment, to A only (optionally including elements other thanB); in another embodiment, to B only (optionally including elementsother than A); in yet another embodiment, to both A and B (optionallyincluding other elements); etc.

As used herein in the specification and in the claims, “or” should beunderstood to have the same meaning as “and/or” as defined above. Forexample, when separating items in a list, “or” or “and/or” shall beinterpreted as being inclusive, i.e., the inclusion of at least one, butalso including more than one, of a number or list of elements, and,optionally, additional unlisted items. Only terms clearly indicated tothe contrary, such as “only one of” or “exactly one of,” or, when usedin the claims, “consisting of,” will refer to the inclusion of exactlyone element of a number or list of elements. In general, the term “or”as used herein shall only be interpreted as indicating exclusivealternatives (i.e. “one or the other but not both”) when preceded byterms of exclusivity, such as “either,” “one of,” “only one of,” or“exactly one of.” “Consisting essentially of,” when used in the claims,shall have its ordinary meaning as used in the field of patent law.

As used herein in the specification and in the claims, the phrase “atleast one,” in reference to a list of one or more elements, should beunderstood to mean at least one element selected from any one or more ofthe elements in the list of elements, but not necessarily including atleast one of each and every element specifically listed within the listof elements and not excluding any combinations of elements in the listof elements. This definition also allows that elements may optionally bepresent other than the elements specifically identified within the listof elements to which the phrase “at least one” refers, whether relatedor unrelated to those elements specifically identified. Thus, as anon-limiting example, “at least one of A and B” (or, equivalently, “atleast one of A or B,” or, equivalently “at least one of A and/or B”) canrefer, in one embodiment, to at least one, optionally including morethan one, A, with no B present (and optionally including elements otherthan B); in another embodiment, to at least one, optionally includingmore than one, B, with no A present (and optionally including elementsother than A); in yet another embodiment, to at least one, optionallyincluding more than one, A, and at least one, optionally including morethan one, B (and optionally including other elements); etc.

It should also be understood that, unless clearly indicated to thecontrary, in any methods claimed herein that include more than one stepor act, the order of the steps or acts of the method is not necessarilylimited to the order in which the steps or acts of the method arerecited.

In the claims, as well as in the specification above, all transitionalphrases such as “comprising,” “including,” “carrying,” “having,”“containing,” “involving,” “holding,” “composed of,” and the like are tobe understood to be open-ended, i.e., to mean including but not limitedto. Only the transitional phrases “consisting of” and “consistingessentially of” shall be closed or semi-closed transitional phrases,respectively, as set forth in the United States Patent Office Manual ofPatent Examining Procedures, Section 2111.03.

1. A process for removing at least one Michael acceptor from acomposition, comprising: treating the composition with athiol-containing compound under conditions sufficient to remove at leasta portion of the at least one Michael acceptor, at least a portion of athiol-Michael adduct which can form from addition of thethiol-containing compound to the at least one Michael acceptor, or atleast a portion of the at least one Michael acceptor and at least aportion of the thiol-Michael adduct, wherein the at least one Michaelacceptor is 14-hydroxycodeinone or salt thereof, wherein thethiol-Michael adduct is a thiol-Michael adduct of 14-hydroxycodeinone,wherein the composition comprises oxycodone or acceptable salt thereof.2. A process for removing at least one Michael acceptor from acomposition, comprising: treating the composition with a suitablesoluble thiol-containing compound under conditions sufficient to reactwith the at least one Michael acceptor, wherein the compositioncomprises oxycodone or acceptable salt thereof; and removing from thecomposition the resulting thiol-Michael adduct, and the unreactedthiol-containing compound, wherein the thiol-containing compound ischosen for its ability to form a soluble thiol-Michael adduct that canbe removed from the composition of interest, and, when desirable,quantified, so as to enable determination of the Michael acceptorcontent of the composition of interest, wherein the at least one Michaelacceptor is 14-hydroxycodeinone or salt thereof, wherein thethiol-Michael adduct is a thiol-Michael adduct of 14-hydroxycodeinone.3. A process of claim 1 wherein the composition is treated with asuitable thiol which has been immobilized on a solid support.
 4. Aprocess of claim 1 comprising producing a product, wherein no singleMichael acceptor or salt thereof is present in an amount exceeding 25ppm.
 5. A process of claim 1 comprising producing a product, wherein nosingle Michael acceptor or salt thereof is present in an amountexceeding 10 ppm.
 6. A process of claim 1 comprising producing aproduct, wherein no single Michael acceptor or salt thereof is presentin an amount exceeding 5 ppm.
 7. A process of claim 1 comprisingproducing a product, wherein no single thiol-Michael adduct or saltthereof is present in an amount exceeding 25 ppm.
 8. A process of claim1 comprising producing a product containing oxycodone or acceptable saltthereof that contains 14-hydroxycodeinone or salt thereof in an amountof less than 25 ppm.
 9. A process of claim 1 comprising producing aproduct containing oxycodone or acceptable salt thereof that contains14-hydroxycodeinone or salt thereof in an amount of less than 10 ppm.10. A process of claim 1 comprising producing a product containingoxycodone or acceptable salt thereof that contains 14-hydroxycodeinoneor salt thereof in an amount of less than 5 ppm.
 11. A process of claim1 comprising producing a product containing oxycodone or acceptable saltthereof that contains 14-hydroxycodeinone or salt thereof in an amountof less than 1 ppm.
 12. A process of claim 2 comprising quantifying atleast one Michael acceptor wherein the amount of thiol-Michael adduct ismeasured and related to the Michael acceptor content of the composition,and wherein the limit of quantification of the amount of any one Michaelacceptor contaminant is 10 ppm or less.
 13. A process of claim 2comprising quantifying the Michael acceptor wherein the amount ofthiol-Michael adduct is measured and related to the Michael acceptorcontent of the composition, and wherein the limit of quantification ofthe amount of any one Michael acceptor contaminant is in the range of0.001-10 ppm.
 14. A process of claim 2 comprising quantifying theMichael acceptor content of the composition or related alkaloid oracceptable wherein the amount of thiol-Michael adduct is measured andrelated to the Michael acceptor content of the composition, and whereinthe limit of quantification of the amount of the Michael acceptorcontaminant is 10 ppm or less.
 15. A process of claim 2 comprisingquantifying the Michael acceptor content of the composition or relatedalkaloid or acceptable wherein the amount of thiol-Michael adduct ismeasured and related to the Michael acceptor content of the composition,and wherein the limit of quantification of the amount of the Michaelacceptor contaminant is 1 ppm or less.
 16. A process of claim 2 whereinthe amount of thiol-Michael adduct is measured and related to theMichael acceptor content of the composition, and wherein the limit ofquantification of the level of the Michael acceptor is in the range of0.001-10 ppm.
 17. A process of claim 2 comprising quantifying the14-hydroxycodeinone content of oxycodone or acceptable salt thereofwherein the amount of thiol-Michael adduct of 14-hydroxycodeinone ismeasured and related to the 14-hydroxycodeinone content of thecomposition, and wherein the limit of quantification of the level of the14-hydroxycodeinone contaminant is 10 ppm or less.
 18. A process ofclaim 2 comprising quantifying the 14-hydroxycodeinone content ofoxycodone or acceptable salt thereof wherein the amount of thiol-Michaeladduct of 14-hydroxycodeinone is measured and related to the14-hydroxycodeinone content of the composition, and wherein the limit ofquantification of the level of the 14-hydroxycodeinone contaminant isless than 1 ppm.
 19. A process of claim 2 comprising quantifying the14-hydroxycodeinone content of oxycodone or acceptable salt thereofwherein the amount of thiol-Michael adduct of 14-hydroxycodeinone ismeasured and related to the 14-hydroxycodeinone content of thecomposition, and wherein the limit of quantification of the level of the14-hydroxycodeinone contaminant is within the range 0.001-10 ppm.
 20. Aprocess of claim 1 wherein the composition comprises an organic basewhose solubility in water decreases with increasing pH; and wherein thecomposition is treated with a suitable thiol-containing compound inaqueous solution at a suitable pH value to form (with the contaminatingMichael acceptor) a soluble thiol-Michael adduct; and wherein theorganic base is then separated from the thiol-Michael adduct and excessthiol-containing compound by raising the pH to a suitable value so as toprecipitate the composition from the solution of soluble thiol-Michaeladduct and excess thiol-containing compound.
 21. A process of claim 2,wherein the composition is separated from thiol-Michael adduct andexcess thiol-containing compound by selective precipitation and/orextraction utilizing water and/or other solvents and/or by selectiveabsorption on media, such as, but not restricted to, ion-exchangeresins, and/or other solid supports containing immobilized ligandedmetal ions, and/or immobilized maleimides, and/or immobilized reactivedisulfides, and/or immobilized antibodies and/or immobilized enzymes.22. A process for removing at least one Michael acceptor, at least oneMichael acceptor hydrate, or at least one Michael acceptor and at leastone Michael acceptor hydrate from a composition, comprising: treatingthe composition with an acidic catalyst under conditions sufficient toremove the at least one Michael acceptor hydrate by converting the atleast one Michael acceptor hydrate to a Michael acceptor, wherein thecomposition comprises oxycodone or acceptable salt thereof; and thentreating the composition with a suitable soluble thiol-containingcompound under conditions sufficient to remove from the composition theunreacted thiol-containing compound, the at least one Michael acceptororiginally present in the composition; and the Michael acceptor formedfrom the at least one Michael hydrate; and wherein the thiol-containingcompound is chosen for its ability to form a soluble thiol-Michaeladduct that can be removed from the composition of interest, and, whendesirable, quantified, so as to enable determination of the Michaelacceptor hydrate content and the Michael acceptor content of thecomposition of interest, wherein the Michael acceptor hydrate is8-hydroxyoxycodone or salt thereof.
 23. A process of claim 22 comprisingproducing a product containing oxycodone or acceptable salt thereof thatcontains 8-hydroxyoxycodone or salt thereof in an amount of less than100 ppm.
 24. A process of claim 22 comprising producing a productcontaining oxycodone or acceptable salt thereof that contains8-hydroxyoxycodone or salt thereof in an amount of less than 10 ppm. 25.A process of claim 22 comprising producing a product containingoxycodone or acceptable salt thereof that contains 8-hydroxyoxycodone orsalt thereof in an amount of less than 5 ppm.